/*
 * Artificial Intelligence for Humans
 * Volume 2: Nature Inspired Algorithms
 * Java Version
 * http://www.aifh.org
 * http://www.jeffheaton.com
 *
 * Code repository:
 * https://github.com/jeffheaton/aifh
 *
 * Copyright 2014 by Jeff Heaton
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * For more information on Heaton Research copyrights, licenses
 * and trademarks visit:
 * http://www.heatonresearch.com/copyright
 */
package com.heatonresearch.aifh.genetic.mutate

import com.heatonresearch.aifh.evolutionary.genome.Genome
import com.heatonresearch.aifh.evolutionary.opp.EvolutionaryOperator
import com.heatonresearch.aifh.evolutionary.train.EvolutionaryAlgorithm
import com.heatonresearch.aifh.genetic.genome.DoubleArrayGenome
import com.heatonresearch.aifh.randomize.GenerateRandom

/**
 * A simple mutation based on random numbers.
 *
 * @param perturbAmount The amount to mutate by(percent).
 */
class MutatePerturb(owner : EvolutionaryAlgorithm,val perturbAmount: Double) extends EvolutionaryOperator(owner,1,1) {

  override def performOperation(rnd: GenerateRandom, parents: Array[Genome], parentIndex: Int,
                                offspring: Array[Genome], offspringIndex: Int) {
    val parent = parents(parentIndex).asInstanceOf[DoubleArrayGenome]
    offspring(offspringIndex) = parent.population.genomeFactory.factor
    val child = offspring(offspringIndex).asInstanceOf[DoubleArrayGenome]
    for(i <- 0 until parent.size) {
      var value = parent.getData(i)
      value += value * (perturbAmount - (rnd.nextDouble * perturbAmount * 2))
      child.getData(i) = value
    }
  }
}